Chest
Total Resistance and Reactance in Patients with Respiratory Complaints with and without Airways Obstruction
Section snippets
Technique
The technique has been described in detail in another publication.8 The seated subject supports his cheeks with his hands and breathes quietly via a screen pneumotachograph through a low impedance side tube; a bias flow reduces the CO2 build-up at the mouth. Simultaneously, a pseudo-random noise pressure signal, containing all harmonics of 2 Hz to 24 Hz with a peak-to-peak amplitude smaller than 0.2 kPa, is applied at the mouth by means of a loudspeaker. Mouth pressure and airflow, recorded by
Total Respiratory Resistance (Rrs) and Reactance (Xrs) vs Frequency (f) Curves
The mean course of Rrs and Xrs vs f in the investigated samples are shown in Figures 1 and 2.
Discriminant Analysis
To investigate which factor best separates healthy subjects from patients with minor complaints with or without slight reductions of FEV1 (samples B and C), first an analysis was performed on sample A (healthy subjects) and the combined samples B and C. Among the investigated ten factors (mean Rrs and Xrs, first four derivatives of Rrs and Xrs), only five turned up to be significant ( , Rrs(1)
DISCUSSION
In patients with manifest COPD, the Rrs and Xrs vs f curves are usually clearly altered:1, 2, 3, 49 there is a frequency dependence of Rrs and the resonant frequency is increased. In milder cases, the alterations of the Rrs and Xrs-f curves may be less pronounced and resemble the tracings sometimes met in presumably healthy subjects. Of course, one may wonder if some of the latter subjects, without complaints and with normal spirographic values, are not in an early stage of a disease, which
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Impact of prenatal and postnatal household air pollution exposure on lung function of 2-year old Nigerian children by oscillometry
2021, Science of the Total EnvironmentCitation Excerpt :We repeated oscillometric measurements every six months, and seasonal variation did not have any significant role in our observations. Evaluating reactance by the oscillometric technique may be useful for early detection of small airway changes (Peters et al., 2018; Oppenheimer et al., 2007) and detecting mild airflow obstruction when there is no change in airway resistance (Peters et al., 2018; Clement et al., 1983). Our observation that X5 at the highest quartile is associated with higher postnatal PM2.5 exposure is very significant because reactance at low frequencies has been correlated with peripheral airway obstruction (Smith et al., 2005).
Recent Diagnosis Techniques in Pediatric Asthma: Impulse Oscillometry in Preschool Asthma and Use of Exhaled Nitric Oxide
2019, Immunology and Allergy Clinics of North AmericaForty years of reference values for respiratory system impedance in adults: 1977–2017
2018, Respiratory MedicineCitation Excerpt :All retained publications were also explored for the differential contribution of sex, age, height, and weight to reported prediction equations. A total of 34 studies providing impedance reference values or prediction equations met inclusion and exclusion criteria and were short-listed for this review [18,20,22,37,39–68]. Table 1 provides a descriptive summary of these studies.
Oscillometry for lung function testing
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Supported by a grant from the Commission of the European Communities.
Manuscript received April 29; revision accepted July 30.